1. Field of the Invention
The present invention relates to a data managing method, a data managing device and a data managing server. More particularly, the present invention relates to a data managing method, a data managing device and a data managing server suitable for restricting distribution of data.
2. Description of the Related Art
In recent years, progression of image digitization technologies and widespread use of networks have been making it easier to optically read images, convert them into digital electronic data, send or receive them through networks, and then record them in other recording media or print them onto other recording media. Along with this, there is a possibility of occurrence of wrong acts of copying documents which are prohibited from being copied, converting them into electronic data and distributing it.
As a technique for preventing such wrong acts, Japanese Laid-Open Patent Publication No. 2001-218022 discloses a method which acquires digital images with permission information embedded therein, extracts the permission information from the digital images and authenticates the permission to generate visualized images of the digital images through an image processing device from the extracted permission information, and after the authenticating step, generates visualized images from the digital images using the image processing device.
However, this method determines whether or not the generation of images is permitted only from the permission information. Therefore, it is impossible to determine whether or not copying images should be permitted depending on the person who intends to copy the images. Namely, images which are prohibited from being copied can not be copied, without exception, regardless of the person who intends to copy them. Therefore, this method can not be employed in the case where copying is permitted for some persons, but not permitted for the others.
Further, with conventional methods, it is possible to prohibit copying of images uniformly. However, for documents which have to be circulated in a predetermined order such as documents which are circulated in a predetermined order in a corporation, it is impossible to permit a person who is later in the circulating order only after persons who are earlier in the circulating order have read the documents.